Giant Magnetoresistive Effect in Fe/Cr Multilayers in a Wide Range of Frequencies

Abstract

Penetration of electromagnetic field through Fe/Cr superlattices in a wide range of frequencies from 0.1 MHz to 38 GHz has been investigated. It is shown that noticeable frequency dependence of the transmission coefficient appears starting from the waves of the meter range. In the ranges of centimeter and millimeter waves, the variation of the transmission coefficient is caused by two physical phenomena: giant magnetoresistance and ferromagnetic resonance. Approximate equality of the values of relative variation of the microwave transmission coefficient and dc magnetoresistance is observed in these frequency ranges far from resonance conditions. A homogeneous mode of ferromagnetic resonance is observed at frequencies of the millimeter range if an external dc magnetic field is directed perpendicular to the plane in which the vectors of ac magnetic field of an electromagnetic wave of the H 10 waveguide mode lie.